80 research outputs found
Anaesthetic aspects of simultaneous aortocaval occlusion
Major elective surgery is known to contribute to intensive care occupancy,
with a significant mortality rate. Routine preoperative optimisation of patients
undergoing major elective surgery is found to give a significant and cost effective
improvement in perioperative care. Criteria that were used to select patients
for routine preoperative optimisation for a large randomised controlled trial
are shown at Table 1. When performing major surgery, the extent of necessary
perioperative monitoring is usually dependent on the view of the anaesthetist,
while the site of postoperative care is dependent on the anticipated development of
complications and the availability of intensive care or high dependency beds
Local Control of Steroid Hormone Biosynthesis
Steroids are essential for vertebrate physiology during pre- and postnatal life. Whereas
the skeleton structure of cyclopenta[α]phenanthrene rings is common to all steroid
molecules, differences occur in methyl- of ethylgroups attached to the four rings or the
oxidation state of the carbon atoms in the rings (Figure 1).1 Endogenous production of
steroids is realized in steroidogenic tissues. From these tissues, steroid molecules can be
secreted into the circulation to act in an endocrine fashion. By binding to receptors in
target tissues they manipulate gene transcription, influencing a wide variety of cellular
functions. Steroids can also exert local effects in the steroidogenic tissues after secretion
into the extracellular space (paracrine or autocrine) or directly within the cell in which
they are produced (intracrine)
Advances in the Diagnosis and Management of Well-Differentiated Neuroendocrine Neoplasms
Neuroendocrine neoplasms constitute a diverse group of tumors that derive from the sensory and secretory neuroendocrine cells and predominantly arise within the pulmonary and gastrointestinal tracts. The majority of these neoplasms have a well-differentiated grade and are termed neuroendocrine tumors (NETs). This subgroup is characterized by limited proliferation and patients affected by these tumors carry a good to moderate prognosis. A substantial subset of patients presenting with a NET suffer from the consequences of endocrine syndromes as a result of the excessive secretion of amines or peptide hormones, which can impair their quality of life and prognosis. Over the past 15 years, critical developments in tumor grading, diagnostic biomarkers, radionuclide imaging, randomized controlled drug trials, evidence-based guidelines, and superior prognostic outcomes have substantially altered the field of NET care. Here, we review the relevant advances to clinical practice that have significantly upgraded our approach to NET patients, both in diagnostic and in therapeutic options
Circulating steroid hormone variations throughout different stages of prostate cancer
Steroid hormones play a central role in the maintenance and progression of prostate cancer. The androgen receptor is the primary driver of tumor cell proliferation and is activated by the androgens testosterone and 5α-dihydrotestosterone. Inhibition of this pathway through medical or surgical castration improves survival in the majority of advanced prostate cancer patients. However, conversion of adrenal androgen precursors and alternative steroidogenic pathways have been found to contribute to tumor progression and resistance to treatment. The emergence of highly accurate detection methods allows us to study steroidogenic mechanisms in more detail, even after treatment with potent steroidogenic inhibitors such as the CYP17A1 inhibitor abiraterone. A clear overview of steroid hormone levels in patients throughout the local, metastatic and castration-resistant stages of prostate cancer and treatment modalities is key toward a better understanding of their role in tumor progression and treatment resistance. In this review, we summarize the currently available data on steroid hormones that have been implicated in the various stages of prostate cancer. Additionally, this review addresses the implications of these findings, highlights important studies in this field and identifies current gaps in literature
Inhibin alpha-subunit (INHA) expression in adrenocortical cancer is linked to genetic and epigenetic INHA promoter variation
Adrenocortical carcinoma (ACC) is a rare, but highly malignant tumor of unknown origin. Inhibin α-subunit (Inha) knockout mice develop ACCs following gonadectomy. In man, INHA expression varies widely within ACC tissues and its circulating peptide inhibin pro-αC has been described as a novel tumor marker for ACC. We investigated whether genetic and epigenetic changes of the INHA gene in human ACC cause loss or variation of INHA expression. To this end, analyses of INHA sequence, promoter methylation and mRNA expression were performed in human adrenocortical tissues. Serum inhibin pro-αC levels were also measured in ACC patients. INHA genetic analysis in 37 unique ACCs revealed 10 novel, heterozygous rare variants. Of the 3 coding bases affected, one variant was synonymous and two were missense variants: S72F and S184F. The minor allele of rs11893842 at -2124 bp was observed at a low frequency (24%) in ACC samples and was associated with decreased INHA mRNA levels: 4.7±1.9 arbitrary units for AA, compared to 26±11 for AG/GG genotypes (P = 0.034). The methylation of four proximal INHA promoter CpGs was aberrantly increased in five ACCs (47.763.9%), compared to normal adrenals (18.4±0.6%, P = 0.0052), whereas the other 14 ACCs studied showed diminished promoter methylation (9.8±1.1%, P = 0.020). CpG methylation was inversely correlated to INHA mRNA levels in ACCs (r =-0.701, p = 0.0036), but not associated with serum inhibin pro-aC levels. In conclusion, aberrant methylation and common genetic variation in the INHA promoter occur in human ACCs and are associated with decreased INHA expression
Prostate cancer androgen biosynthesis relies solely on CYP17A1 downstream metabolites
Prostate cancer (PC) is dependent on androgen receptor (AR) activation by testosterone and 5α-dihydrotestosterone (DHT). Intratumoral androgen accumulation and activation despite systemic androgen deprivation therapy underlies the development of castration-resistant PC (CRPC), but the precise pathways involved remain controversial. Here we investigated the differential contributions of de novo androgen biosynthesis and androgen precursor conversion to androgen accumulation. Steroid flux analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed on (CR)PC cell lines and fresh patient PC tissue slices after incubation with classic and alternative biosynthesis intermediates, alongside quantitative PCR analysis for steroidogenic enzyme expression. Activity of CYP17A1 was undetectable in all PC cell lines and patient PC tissue slices. Instead, steroid flux analysis confirmed the generation of testosterone and DHT from adrenal precursors and reactivation of androgen metabolites. Precursor steroids upstream of DHEA were converted down the first steps of the alternative DHT biosynthesis pathway, but did not proceed through to active androgen generation. Comprehensive steroid flux analysis of (CR)PC cells provides strong evidence against intratumoral de novo androgen biosynthesis and demonstrates that androgen precursor steroids downstream of CYP17A1 activities constitute the major source of intracrine androgen generation.</p
COVID-19-associated immune thrombocytopenia
Thrombocytopenia is a risk factor for increased morbidity and mortality in patients with the new severe acute respiratory syndrome corona virus, SARS-CoV-2 infection (COVID-19 infection).1 Thrombocytopenia in COVID-19 patients may be caused by disseminated intravascular coagulation (DIC), sepsis or drug-induced. Recently a single case report suggested immune thrombocytopenia (ITP) may be associated with COVID-19 infection.2 ITP is a rare autoimmune disease characterized by a platelet count < 100x109/L, leading to an increased bleeding risk.3 Several risk factors have been described for ITP including environmental (e.g. infection, malignancy and drugs) and genetic predisposition.4 We report here the first case series of three patients with ITP associated with COVID-19 infection
Validation of circulating steroid hormone measurements across different matrices by liquid chromatography–tandem mass spectrometry
Background: Steroid hormones are essential signalling molecules in prostate cancer (PC). However, many studies focusing on liquid biomarkers fail to take the hormonal status of these patients into account. Steroid measurements are sensitive to bias
Targeted Systemic Treatment of Neuroendocrine Tumors: Current Options and Future Perspectives
Neuroendocrine tumors (NETs) originate from the neuroendocrine cell system in the bronchial and gastrointestinal tract and can produce hormones leading to distinct clinical syndromes. Systemic treatment of patients with unresectable NETs aims to control symptoms related to hormonal overproduction an
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